Ultrasonography/MRI Versus CT for Diagnosing Appendicitis

Radiation-Free Diagnosis of Acute Appendicitis in Children

With over 70,000 children diagnosed with appendicitis annually, it is the most common reason for acute abdominal surgery in children less than 18 years old. Appendicitis is an inflammation of the appendix, which is a several centimeter long outpouching near the junction of the small and large intestine (see image). Appendicitis is considered a surgical emergency and, left untreated, could lead to the potentially life-threatening complication of perforation. Perforation, or rupture of the appendix, is a spillage of its inflamed contents into the abdomen, possibly leading to a more widespread infection. Thus, accurate diagnosis of appendicitis is important to avoid unnecessary surgery and complications of delayed diagnosis.

The current gold standard imaging technique used to diagnosed appendicitis in children is a CT scan. CT, which stands for computed tomography, uses computer-processed x-rays to produce several detailed cross-sectional images of the inside of the body. In the diagnosis of appendicitis, CT is advantageous in that there is less variability in interpretation of its results, it provides a good view of the appendix, and the image quality is less affected by obesity, abdominal gas or pain. The main disadvantage to using CT is radiation. This is of particular concern as children are more sensitive to radiation, particularly after repeated exposures.

Previous studies have shown that radiation free imaging, such as MRI, is feasible and effective in diagnosing appendicitis in children. A recent study extended this line of research by investigating how radiation free imaging (ultrasound followed by MRI) compared to CT scans in the outcomes of appendicitis in children. The study reviewed hospital records of 662 children who presented to a large New York children’s emergency department with symptoms suspicious of appendicitis. Group A consisted of 265 children who presented to the ED prior to 2010 when the gold standard imaging modality for appendicitis was CT scan. Group B consisted of 397 who presented to the ED after 2010 when the primary imaging modality was ultrasound followed by MRI. 142 patients in Group B received an MRI only after an ultrasound was found to have unclear results.

A comparison of the data between Group A and Group B demonstrated no significant difference in the following clinical outcomes:

Rate of negative appendectomy (imaging showed appendicitis, but the operation did not reveal an inflamed appendix)

Rate of perforations

Time from triage to administration of antibiotics

Time from triage to operation

Length of stay in hospital

Data also showed the diagnostic accuracy to be statistically similar between the two types of imaging. These results indicate that radiation-free imaging with ultrasound followed by MRI in select cases is effective and comparable to the use of CT scan in suspected cases of appendicitis in children and should be considered as the primary imaging modality by emergency physicians to reduce radiation exposure in children.

What this means for you

If your child has symptoms which are concerning for appendicitis, it may no longer be necessary to expose them to radiation to confirm the diagnosis. It will be some time before MRI and ultrasound completely replace CT scanning in the diagnosis of appendicitis, but this article will help expedite the process. While the implications are more behind the scenes, it translates to safer health care for everyone.